If the version you are using are VMware ESX 3 and Virtual Center 2 then you can do the following to avoid this problem.

1- Launch VI Client and connect to the VirtualCenter Server host system.
2- Select the virtual machine that you want to migrate (by selecting Inventory (from the navigation bar) and navigating to the virtual machine, or by simply clicking on its name in the inventory panel.)
3- Click Edit Settings (in the Commands section of the Summary tab). The Properties page for the virtual machine displays.
4- Click the Options tab in the Properties page.
5- Select Advanced (under Settings on the Options tab) to display several settings-related boxes, including CPU Identification Mask, in the right-hand pane.

For every virtual machine that you want to migrate (that doesn’t meet CPU compatibility constraints for VMotion), you’ll navigate to the CPU Identification Mask section of the Properties-->Options page for starters.

Modifying Default NX/XD MaskIf you encounter a CPU feature compatibility issue with the NX/XD bit, you may be presented with the following error:

The CPU of the host is incompatible with the cpu feature requirements of virtual machine; problem detected at CPUID level 0x80000001 register 'edx'.

To modify the mask to enable or disable the NX/XD CPU bit:
1- Navigate to the virtual machine’s Properties page-->Options tab (see steps above, if necessary).
2- Click either the Hide the NX flag from guest or the Expose the NX flag to guest radio button to disable or enable this CPU compatibility check for the selected virtual machine as shown in the image below
4- Click OK to save the change.
Note: The NX/XD mask can only be modified when the virtual machine is powered off.

Modifying Default Mask for Intel1- Navigate to the virtual machine’s Properties page-->Options tab (see steps above, if necessary).
2- Click Advanced... to open the CPU Identification Mask properties dialog box. Note that the CPU Identification Mask dialog box has two tabs—Virtual Machine Default, and AMD Override. Most modifications for Intel CPU features are made on the Virtual Machine Default page. Modifications for AMD CPU features are made on the AMD Overrides page.
3- Click the Virtual Machine Default tab to activate the dialog box, if necessary.
4- modify the mask for a specific feature, enter the series of dashes and 0s as shown below

Unfortunately you will have to repeat the steps above for every virtual machine.

Note: The masks provided will disable most of the CPU Compatibility checks for that virtual machine. If it work for you then you might want to eliminate the specific failing feature. To do that you can check the following VMware article: http://kb.vmware.com/selfservice/micros ... nalId=1993